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Malaria-resistant Mosquitoes Battle Disease With 'Molecular Warhead'   Message List  
Reply | Forward Message #121 of 188 |
Engineered Mosquitoes Could Wipe Out Dengue Fever

I saw Jurassic Park. This will end badly.


Engineered Mosquitoes Could Wipe Out Dengue Fever
By Alexis Madrigal 01.23.08 | 1:05 PM
http://www.wired.com/science/planetearth/news/2008/01/gm_insects

Scientists at a British biotech company said they have evidence that
their genetically modified mosquitoes, which are programmed for sudden,
early death, can control the spread of dengue fever.
Dengue is carried by mosquitoes and is the scourge of urban areas in the
developing world, much as malaria is in rural regions. The company,
Oxitec, said it can decimate mosquito populations by breeding
genetically modified male mosquitoes, then releasing them to mate with
wild females. Their offspring contain lethal genes that kill them young,
before they can reproduce. Company officials told Wired News that their
latest test results show that the genetically modified bugs can breed
just as well as wild ones.
"We will be able to control dengue through controlling the mosquitoes
that transmit it, especially in large urban areas," said the company's
chief scientist Luke Alphey. "Thereby protecting many, many millions of
people from this disease."
Mosquitoes pass dengue fever to up to 100 million people each year,
according to the Centers for Disease Control and Prevention. Up to 5
million die. If the scientists can replicate their results in real field
conditions, their technology could kill half of the next generation of
dengue mosquitoes, which scientists say would significantly reduce the
spread of the disease. If all goes well the company envisions releasing
the insects in Malaysia on a large scale in three years.
Oxitec's latest research, which company scientists will present in
February at the IX International Symposium on Vectors and Vector-borne
Diseases in Puri, India, included an independent evaluation by
Malaysia's Institute for Medical Research, part of the country's
Ministry of Health, said S.S. Vasan, Oxitec's head of public health, in
an e-mail. The results showed that up to 50 percent of wild female
mosquitoes mated with Oxitec's genetically modified male mosquitoes.
The company's work has attracted the interest of some of the world's
economic honchos. At the Davos Economic Forum this week, Alphey will
receive one of 39 Technology Pioneer Awards. The Gates Foundation's
Global Challenges in Global Health initiative is giving Oxitec $5
million over the next five years. The company has also received several
million dollars in venture capital from East Hill Management Company and
Oxford Capital Partners.
Oxitec's technology is a variation of a proven process called "sterile
insect technique," which scientists have already used to eliminate the
screwworm and the Mediterranean fruit fly from North America. It
involves irradiating male insects, causing mutations that make them
sterile. When released into the wild, they mate with females who then
fail to reproduce.
But the amount of radiation used in that technique kills mosquitoes. So
in a twist on the sterile insect technique, Alphey discovered a way to
genetically program the bugs to die unless they're fed the common
antibiotic tetracycline.
By postponing death with tetracycline, the scientists can keep the
altered bugs alive long enough to breed them in large numbers. When
released into the wild, they no longer receive tetracycline so the
previously silenced gene springs into action. The bugs stay alive long
enough to breed with wild females, but their offspring die young.
In other words, the mosquitoes are genetically poisoned, but Alphey's
team provides the antidote until they are released in the wild.
"It occurred to me that this could be used to give death, sterility or
whatever you want in insects," Alphey said.
Alphey's approach to genetic modification is different from other
research on so-called population replacement efforts, which aim to
"inoculate" the mosquito population against dengue, which would, in
turn, prevent them from passing it to humans. Oxitec's technique is
considered less controversial by some scientists because the genetically
modified insects are programmed to die, not take over the existing
mosquito population.
But as with genetically modified crop companies like Monsanto, Oxitec
could face a backlash from a wary public. Greenpeace, among others,
oppose genetic engineering of organisms that could be released into the
wild.
"Releasing millions of genetically modified terminator mosquitoes into
wild ecosystems amounts to a reckless and uncontrolled experiment with a
risky technology," said Jim Thomas, of the ETC Group, a technology
watchdog. "Oxitec's (project) abandons all pretense of containment or
possible recall. I wonder what sort of liability they are willing to
assume if something goes wrong?"
Thomas also questioned Oxitec's core technology -- a regulatory switch
that uses tetracycline.
"The assumption is that the insects will not encounter tetracycline in
the wild and yet tetracycline, naturally derived from a soil bacteria,
is widely used in agriculture," Thomas said.
"Genetically engineered insects for pest control are a literal disaster
waiting to happen," said Ronnie Cummins, director of the Organic
Consumers Association, in an e-mail.
Alphey, however, believes the benefits -- potentially combating dengue
as well as cutting down on pesticide use -- will stave off public
protests.
"Clearly, there will be people who are completely closed to the idea, no
matter what the benefit," Alphey said. "But ... people know about
malaria and dengue and these sorts of things. They know they don't want
them. They really see the point in what people (like us) are trying to
do."
Thomas Miller, an entomologist at the University of California at
Riverside who has worked with Alphey on a cotton-crop pest, said the
current mosquito population control options are not good.
They generally involve using insecticides or destroying their
standing-water larval hatching grounds. In urban areas where dengue
fever mosquitoes grow, however, it has proven difficult to eliminate
small sources of water in empty coke cans, spare tires and gutters. On
the other hand, low-tech options like bed nets have helped reduce rates
of mosquito-borne infection, without reducing mosquito populations.
Oxitec is also working on genetically modified versions of fruit flies,
pink bollworms and coding moths.




Thu Jan 24, 2008 3:46 pm

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Malaria-resistant Mosquitoes Battle Disease With 'Molecular Warhead' Science Daily — A team led by UT Southwestern Medical Center researchers has discovered...
Russell, Benjamin
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Jul 9, 2007
7:44 pm

I saw Jurassic Park. This will end badly. Engineered Mosquitoes Could Wipe Out Dengue Fever By Alexis Madrigal 01.23.08 | 1:05 PM ...
Loyal Philip Hall
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Jan 24, 2008
3:47 pm
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